Color Calibration — Why Should We Do This and What is it Anyway?

Color Calibration – Why we should do this and what is it in the first place.

Last week we had a very informative meeting presented by one of our finest photographic artists in the club. He certainly knows his stuff, but I had this nagging feeling that there were many around me asking two questions. What does calibration actually do and why should I do it.

I’m going to handle this in the reverse order. Why Calibrate? The answer is simple. To enable yourself to take a picture from whatever source you receive it whether from a camera, the web, email, scanned or drawn image and have it appear as you expect on other devices such as home printers, online printing labs or at the local office Depot.

What happens when calibrating the first and most critical output device; your monitor?

I’m going to get a bit technical here, hopefully simply technical. Your computer is colorblind. It doesn’t know what a color is, but it knows what numbers are. For web sites, the way we represent colors is with a six place code. Two places to determine red, two to determine green and two to determine blue. For each color there are 255 possibilities and you can mix and match them. So for red, it would be represented to the computer as ff0000. This means to display all the red you can with the highest possible number; FF and no green or blue represented by the four zeroes. The computer has it. Red. I mean red red. It’s red man. However your monitor needs to be calibrated so that this shade and brightness of red correctly displayed. If you look at this on the windows computer I used to write this, you’ll probably have one shade of red. Plug in a different brand of monitor and you get a different shade or even a little blue or green into the picture.

So calibrating your monitor guarantees that red will be red. For the average person, you can do this by eye for the most part if you follow the directions for calibrating your monitor. Whatever you do though, don’t forget to squint. That’s the secret to success with this method.

For Macs, here’s some short instructions to get started. Don’t worry about the simplicity of the instructions. Just dive right in and follow what appears on the screen. It’s easy and did I mention, when it says squint. Squint! http://tinyurl.com/CalibrateMac

For Windows computers it’s a little more complicated, but not much harder. These instructions generally work for windows xp (you really still have xp?) Windows Vista, or Windows 7.

This is actually somewhat of a misnomer. It should be calibrate your paper and ink. Most printers can perform a generally decent calibration to the non-photo aficionado by controlling the quality of ink and using as white a paper as you can find. So if you have recent Epson, HP, Cannon or other major name brand printer you’ll do well just using automatic settings. It won’t be exact this way, but it will be for the most part good enough, but if you’re going to get fancy or picky, read on.

Paper comes in all kinds of shades and colors, even white paper. Your ink color changes based on the color behind it simply because the ink will never overcome the paper color completely. This is because your printer is laying down dots. So if you’re printing on sepia or beige paper, use the largest dots per inch available so that there is less of the non-white color showing through. And keep in mind, what is white in your image will not be white on non-bright-white paper. This is caused by the fact that white is the one color that no ink is placed on the page.

Your printer will receive the same instructions as your monitor. The printer will say print red (ff0000) and the printer will print its version of that red. Now here’s where the ideas of profiles enter in. Profiles are simply a table that the computer will refer to that adjusts the printers idea of red to match what the computer says is red. Let’s say that your printer achieves that perfect red at FF0000 minus three red points. The perfect Green at 00FFF00 minus two green points and it’s dead right on blue at 0000ff. A profile table in human terms would look like this.

Computer

Adjustment

Printer

Result

FF Red

-3

FC

Pure Red

FF Green

-2

FD

Pure Green

FF Blue

0

FF

Pure Blue

What about calibration tools?

It’s reasonable to expect close results from an Apple screen to another apple screen on a different mac just by “eyeballing” your calibration. However this is nearly impossible on printers with the naked eye. Most printers have a decent idea on how to come close, but what if your needs are exact. Calibration scanners that can calibrate printers and projectors will read the colors to find out the difference between what the printer produces for its output and what the output should be. Then it builds a table similar to the one above to match what the computer says is read to the same color on your printer.

Why is all this important.

Are you shopping for a blue sweater or a green one? Did you notice that most web sites that sell clothing always put text under the photo stating the color of the product? However surprises can still occur when you open the package. Calibrating your monitor will guarantee a much closer match of what’s in the package you receive compared to what’s on your screen. You’ll be less disappointed.

For the web professional with a store, if a customer buys the wrong color sweater because you were not calibrated correctly, you probably won’t be doing the next batch of graphics for that site again. Having your screen calibrated means that you can demonstrate competence when you teach your customer how to calibrate their screens. It also means fewer proof prints will be necessary if they can reproduce on their screen what you see on yours. So do share with your clients how to at least eyeball it. Or impress them and get it 100% right. Pay a visit and calibrate their screens. They’ll love you for it.

Bringing the idea of calibration home.

In the early days of television, often skin tone looked, well, wrong without makeup. So makeup was often used and color shifted a bit. Though I cannot find a color example, it has been often said that this good looking couple and couples like them would have had a somewhat green tint of makup in order to make their skin tone look soft and natural in black and white television. So they might have looked a little like this so if this old story is true, the color was calibrated so that the film or video would look right to your eyes. That’s what calibration is all about.